As a new type of energy-saving and environmentally-friendly light source, a light emitting diode (LED) has many advantages, such as its small size, fast response time and long service life. LCD TVs can achieve higher contrast ratios, higher brightness levels and higher color saturations by using LEDs as backlights. Additionally, the LED is a semiconductor solid light source which does not contain any toxic substances. The LED light source is gradually replacing traditional backlights as an environmentally-friendly light source.
However, the LED itself does have some shortcomings. For example, the forward I-V characteristics of an LED are very steep because an LED typically has very small forward dynamic resistance. When the voltage between both ends of an LED has a slight change, the current flowing through the LED will change greatly. As a current-driven component, the brightness of an LED will vary with changes in current. Even if the current is constant, the brightness of an LED can also drift when the temperature rises. Changes in the brightness of an LED will bring about changes in its color. All of these issues affect the performance of LEDs as backlights and may negatively impact picture quality.